This paper provides an introduction to the ecological features that characterise the wetlands of the Kakadu region in tropical northern Australia, including gaps in the understanding of the ecosystem services they provide, and a comment on the emergence of novel ecosystems as a consequence of global change, in particular sea-level rise and an anticipated transition of freshwater wetlands to saline conditions.

Sediment fluxes and sinks based on total sediment load for Magela Creek in the Australian wet–dry tropics have been constructed from detailed measurements of turbidity, suspended sand and bedload for the 10-year period from 2001–2002 to 2010–2011. The present work showed that the sediment-trap efficiency of the vegetated wetlands on lower Magela is high at ~89.5%.

Consideration of ecological processes is required to ensure the success of ecological restoration and conservation activities. An assessment was conducted to ensure that current and future environmental monitoring programs are in place to safeguard the protection of aquatic ecological processes, particularly in the context of rehabilitation of Ranger uranium mine.

Mangroves in Kakadu National Park in Australia’s Northern Territory have undergone significant changes, occupying much of the lowlands c. 6000 years ago, but are now confined to the river margins and islands. Recent observations from satellite and aircraft have indicated that fluctuations in sea level exert a significant effect on the distribution of mangroves, with a drop in the sea level from 2015 to 2016 contributing to unprecedented dieback on the landward margins. 

The coastal floodplains of the Kakadu Region of northern Australia are highly vulnerable to future sea level rise (SLR) and extreme weather events. A hydrodynamic model was developed to simulate the frequency and extent of saltwater inundation of future SLR scenarios from 2013 to 2100 (1.1 m above mean sea level), and was used to assess potential risk to freshwater floodplains.

The magpie goose is an iconic tropical species highly valued as a conservation asset and by Aboriginal people as a cultural resource. Their spatial and temporal dynamics in the Kakadu Region of Northern Australia are characterised at seasonal and decadal time scales using long-term aerial survey data. The customary harvesting practices of geese and their eggs in the region show that their cultural value extends beyond consumption of bush-food.

Key stream fauna in Kakadu National Park face severe threats in 100+ years associated with climate change, invasive species, and mine-site rehabilitation. Sea level rise will salt the coastal floodplains and the fauna must then rely on reduced upstream refuges vulnerable to strong swings between more intense El Niños and La Niñas. Rates and extremes of future climate change appear unprecedented, making predictions associated with past climate change unreliable.

Sea-level rise associated with global warming will increase across Kakadu causing widespread saltwater intrusion. We aimed to understand how soil bacteria might respond to these impacts, by sampling transects in different river zones. We found diverse bacterial communities that were sensitive to soil variables, suggesting that saltwater intrusion may affect bacterial contributions to the dynamic floodplain ecosystems of Kakadu.

On the Kakadu floodplains, the distribution of different plant communities varies yearly, related to flooding duration and water depth. Because these floodplains are close to the coast, they are vulnerable to saltwater intrusion as the sea levels rise. The most obvious effect of this will be the transformation from freshwater vegetation to salt-tolerant plants in susceptible areas.

The floodplains of Kakadu National Park in northern Australia are under threat from saltwater intrusion. To evaluate the impact from this threat, we used molecular approaches to determine the composition of eukaryotic soil communities in the South Alligator River floodplain. Our results suggest that both salinity and pH play a dominant role in shaping the eukaryote communities.

We have developed an approach to assess sea-level rise effects on socio-ecological systems, using Yellow Water wetland on Kakadu National Park as a case study. Sea-level rise will cause profound changes in the Park, but it may also provide an opportunity to bring together Indigenous and non-Indigenous knowledge towards a commonly perceived threat. Strategies that facilitate Indigenous people’s participation in research and monitoring programs are needed to improve understanding of impacts and enhance adaptive capacity.

The floodplains of the Kakadu Region, world-renowned for their natural and cultural values, are threatened by invasive species and future sea-level rise. A risk assessment that integrates both threats to multiple values out to 2100 was undertaken, and suggested that floodplains will likely transform to marine-dominated ecosystems that cannot be managed back to previous conditions. The study highlighted the importance of freshwater refugia because both their value and vulnerability will increase over time.